title: Enantioselective access to benzannulated spiroketals using a chiral sulfoxide auxiliary.
abstract: This article describes our efforts to develop an asymmetric synthesis of bisbenzannulated spiroketals using a chiral sulfoxide auxiliary. Our primary focus was on the synthesis of the 3H-spiro[benzofuran-2,2'-chroman] ring system, the spirocyclic core of the rubromycin family. Our strategy employed the use of lithium-halogen exchange on a racemic bromospiroketal in order to attach a chiral sulfoxide, thus producing two diastereomers. The diastereomers were separable, enabling isolation of each spiroketal enantiomer. Subsequent cleavage of the sulfoxide group from each diastereomer yielded the respective parent spiroketal in high enantiopurity.
authors.affiliation: School of Chemical Sciences, University of Auckland, 23 Symonds Street, Auckland 1142, New Zealand.
authors.forename: Harry R M
authors.initials: HR
authors.lastname: Aitken
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Furkert
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Hubert
authors.forename: James M
authors.initials: JM
authors.lastname: Wood
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Brimble
mesh_terms: D001554:Benzene / Q000737:chemistry*; D005663:Furans / Q000737:chemistry*; D015394:Molecular Structure; D011809:Quinones / Q000737:chemistry; D012451:Safrole / Q000031:analogs & derivatives* / Q000737:chemistry; D013141:Spiro Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D005663:Furans; D011809:Quinones; D013141:Spiro Compounds; C520774:spiroketal; C064949:gamma-rubromycin; D001554:Benzene; D012451:Safrole; C005746:sulfoxide